2002 xterra supercharged engine distributor seized. Took it to local shop, they replaced the distributor and said it ran rough for about a minute and then cut off. now it will crank but no start. The mechanic said that when the distributor froze it damaged the camshaft and would cost a couple grand to repair. Any insight if this is what really happened or how to check it out would be greatly appreciated. Truck is in perfect shape and don't want to scrap it.